scholarly journals Evolutionary History of Lake Tanganyika’s Predatory Deepwater Cichlids

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Paul C. Kirchberger ◽  
Kristina M. Sefc ◽  
Christian Sturmbauer ◽  
Stephan Koblmüller
Keyword(s):  
Phylogenetic Trees ◽  
Lake Tanganyika ◽  
Introgressive Hybridization ◽  
Secondary Contact ◽  
Aflp Data ◽  
Cichlid Species ◽  
Mitochondrial Data ◽  
Allopatric Divergence ◽  
Molecular Phylogenetic ◽  
History Of

Hybridization among littoral cichlid species in Lake Tanganyika was inferred in several molecular phylogenetic studies. The phenomenon is generally attributed to the lake level-induced shoreline and habitat changes. These allow for allopatric divergence of geographically fragmented populations alternating with locally restricted secondary contact and introgression between incompletely isolated taxa. In contrast, the deepwater habitat is characterized by weak geographic structure and a high potential for gene flow, which may explain the lower species richness of deepwater than littoral lineages. For the same reason, divergent deepwater lineages should have evolved strong intrinsic reproductive isolation already in the incipient stages of diversification, and, consequently, hybridization among established lineages should have been less frequent than in littoral lineages. We test this hypothesis in the endemic Lake Tanganyika deepwater cichlid tribe Bathybatini by comparing phylogenetic trees of Hemibates and Bathybates species obtained with nuclear multilocus AFLP data with a phylogeny based on mitochondrial sequences. Consistent with our hypothesis, largely congruent tree topologies and negative tests for introgression provided no evidence for introgressive hybridization between the deepwater taxa. Together, the nuclear and mitochondrial data established a well-supported phylogeny and suggested ecological segregation during speciation.

scholarly journals The Evolutionary History, Diversity, and Ecology of Willows (Salix L.) in the European Alps

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 146
Author(s):  
Natascha D. Wagner ◽  
Li He ◽  
Elvira Hörandl
Keyword(s):  
Habitat Preferences ◽  
Introgressive Hybridization ◽  
Ecological Factors ◽  
The Arctic ◽  
Secondary Contact ◽  
European Alps ◽  
Climatic Fluctuations ◽  
History Of ◽  
European Mountain ◽  
The Alps

The genus Salix (willows), with 33 species, represents the most diverse genus of woody plants in the European Alps. Many species dominate subalpine and alpine types of vegetation. Despite a long history of research on willows, the evolutionary and ecological factors for this species richness are poorly known. Here we will review recent progress in research on phylogenetic relationships, evolution, ecology, and speciation in alpine willows. Phylogenomic reconstructions suggest multiple colonization of the Alps, probably from the late Miocene onward, and reject hypotheses of a single radiation. Relatives occur in the Arctic and in temperate Eurasia. Most species are widespread in the European mountain systems or in the European lowlands. Within the Alps, species differ ecologically according to different elevational zones and habitat preferences. Homoploid hybridization is a frequent process in willows and happens mostly after climatic fluctuations and secondary contact. Breakdown of the ecological crossing barriers of species is followed by introgressive hybridization. Polyploidy is an important speciation mechanism, as 40% of species are polyploid, including the four endemic species of the Alps. Phylogenomic data suggest an allopolyploid origin for all taxa analyzed so far. Further studies are needed to specifically analyze biogeographical history, character evolution, and genome evolution of polyploids.

scholarly journals Jumping through the hoops: the challenges of daffodil (Narcissus) classification

2019 ◽  
Vol 190 (4) ◽  
pp. 389-404 ◽  
Author(s):  
Kálmán Könyves ◽  
John David ◽  
Alastair Culham
Keyword(s):  
Dna Sequences ◽  
Phylogenetic Trees ◽  
Plastid Dna ◽  
Microsatellite Data ◽  
Population Sampling ◽  
Molecular Phylogenetic ◽  
History Of ◽  
Nuclear Microsatellite ◽  
Congruent Group ◽  
First Time

Abstract Hoop-petticoat daffodils are a morphologically congruent group comprised of two distinct lineages in molecular phylogenetic trees of Narcissus. It is possible that the morphological similarity is a product of both historic and current low-level gene flow between these lineages. For the first time, we report population sampling from across the entire range of distribution covering the Iberian Peninsula and Morocco. In total, 455 samples were collected from 59 populations. Plastid DNA sequences of matK and ndhF were generated alongside 11 microsatellite loci to permit comparison between plastid and nuclear lineage histories. The plastid DNA phylogenetic tree was highly congruent with previous molecular studies and supported the recognition of these two lineages of hoop-petticoat daffodils as separate sections. Assignment of samples to sections sometimes differed between plastid DNA and (nuclear) microsatellite data. In these cases, the taxa had previously been the focus of dissent in taxonomic placement based on morphology. These discrepancies could be explained by hybridization and introgression among the two lineages during the evolution of hoop-petticoat daffodils, and shows that placement of species in sections is dependent on the source of data used. This study underlines the complex evolutionary history of Narcissus and highlights the discrepancies between floral morphology and phylogeny, which provides a continuing challenge for the systematics of Narcissus.

scholarly journals Tuber Fulgens Quél. A New Record for Turkish Truffles

2020 ◽  
Vol 8 (11) ◽  
pp. 2472-2475
Author(s):  
Ilgaz Akata ◽  
Mustafa Sevindik ◽  
Ergin Şahin
Keyword(s):  
Phylogenetic Trees ◽  
Sequence Similarity ◽  
Large Subunit ◽  
Morphological Data ◽  
Lsu Rdna ◽  
High Sequence Similarity ◽  
Rdna Sequences ◽  
Molecular Phylogenetic ◽  
History Of ◽  
First Time

Tuber samples were collected from Kırklareli province on the 10th of August 2020 and they are identified by implementing both traditional methods and molecular phylogenetic analysis using the rDNA sequences including Internal Transcribed Spacer (ITS) and 28S Ribosomal Large Subunit (LSU) regions. By taking into account the high sequence similarity between the collected samples (ANK Akata 7351) and the truffle species Tuber fulgens Quél. the collected specimen was regarded as T. fulgens and the morphological data also consolidated this finding. As a result, T. fulgens was reported for the first time from Turkey. A short description of the newly reported species is given along with its macro and microphotographs, and spore images taken by a scanning electron microscope (SEM). Additionally, ITS and LSU rDNA based evolutionary history of the specimen is provided with phylogenetic trees.

Allopatric divergence and secondary contact with gene flow: a recurring theme in rattlesnake speciation

2019 ◽  
Vol 128 (1) ◽  
pp. 149-169 ◽  
Author(s):  
Drew R Schield ◽  
Blair W Perry ◽  
Richard H Adams ◽  
Daren C Card ◽  
Tereza Jezkova ◽  
...  
Keyword(s):  
Gene Flow ◽  
Demographic History ◽  
Secondary Contact ◽  
Tree Model ◽  
Crotalus Viridis ◽  
Species Complexes ◽  
Isolating Mechanisms ◽  
Allopatric Divergence ◽  
History Of ◽  
Study Population

Abstract The study of recently diverged lineages whose geographical ranges come into contact can provide insight into the early stages of speciation and the potential roles of reproductive isolation in generating and maintaining species. Such insight can also be important for understanding the strategies and challenges for delimiting species within recently diverged species complexes. Here, we use mitochondrial and nuclear genetic data to study population structure, gene flow and demographic history across a geographically widespread rattlesnake clade, the western rattlesnake species complex (Crotalus cerberus, Crotalus viridis, Crotalus oreganus and relatives), which contains multiple lineages with ranges that overlap geographically or contact one another. We find evidence that the evolutionary history of this group does not conform to a bifurcating tree model and that pervasive gene flow has broadly influenced patterns of present-day genetic diversity. Our results suggest that lineage diversity has been shaped largely by drift and divergent selection in isolation, followed by secondary contact, in which reproductive isolating mechanisms appear weak and insufficient to prevent introgression, even between anciently diverged lineages. The complexity of divergence and secondary contact with gene flow among lineages also provides new context for why delimiting species within this complex has been difficult and contentious historically.

scholarly journals Topology Testing and Demographic Modeling Illuminate a Novel Speciation Pathway in the Greater Caribbean Sea Following the Formation of the Isthmus of Panama

2021 ◽  
Author(s):  
Benjamin M. Titus ◽  
H. Lisle Gibbs ◽  
Nuno Simões ◽  
Marymegan Daly
Keyword(s):  
Gene Flow ◽  
Species Complex ◽  
Phylogenetic Analyses ◽  
Secondary Contact ◽  
Test Species ◽  
Demographic Modeling ◽  
Isthmus Of Panama ◽  
Allopatric Divergence ◽  
History Of ◽  
Topology Testing

AbstractRecent genomic analyses have highlighted the prevalence of speciation with gene flow in many taxa and have underscored the importance of accounting for these reticulate evolutionary processes when constructing species trees and generating parameter estimates. This is especially important for deepening our understanding of speciation in the sea where fast moving ocean currents, expanses of deep water, and periodic episodes of sea level rise and fall act as soft and temporary allopatric barriers that facilitate both divergence and secondary contact. Under these conditions, gene flow is not expected to cease completely while contemporary distributions are expected to differ from historical ones. Here we conduct range-wide sampling for Pederson’s cleaner shrimp (Ancylomenes pedersoni), a species complex from the Greater Caribbean that contains three clearly delimited mitochondrial lineages with both allopatric and sympatric distributions. Using mtDNA barcodes and a genomic ddRADseq approach, we combine classic phylogenetic analyses with extensive topology testing and demographic modeling (10 site frequency replicates x 45 evolutionary models x 50 model simulations/replicate = 22,500 simulations) to test species boundaries and reconstruct the evolutionary history of what was expected to be a simple case study. Instead, our results indicate a history of allopatric divergence, secondary contact, introgression, and endemic hybrid speciation driven by the final closure of the Isthmus of Panama and the strengthening of the Gulf Stream Current ~3.5 million years ago. The history of this species complex recovered by model-based methods that allow reticulation differs from that recovered by standard phylogenetic analyses and is unexpected given contemporary distributions. The geologically and biologically meaningful insights gained by our model selection analyses illuminate a novel pathway of species formation that resulted from one of the most biogeographically significant events in Earth’s history.

scholarly journals Synthesizing and databasing fossil calibrations: divergence dating and beyond

2011 ◽  
Vol 7 (6) ◽  
pp. 801-803 ◽  
Author(s):  
Daniel T. Ksepka ◽  
Michael J. Benton ◽  
Matthew T. Carrano ◽  
Maria A. Gandolfo ◽  
Jason J. Head ◽  
...  
Keyword(s):  
Phylogenetic Trees ◽  
Interdisciplinary Collaboration ◽  
Branch Length ◽  
Molecular Data ◽  
Primary Objective ◽  
Calibration Data ◽  
Fossil Calibration ◽  
Divergence Dating ◽  
Molecular Phylogenetic ◽  
History Of

Divergence dating studies, which combine temporal data from the fossil record with branch length data from molecular phylogenetic trees, represent a rapidly expanding approach to understanding the history of life. National Evolutionary Synthesis Center hosted the first Fossil Calibrations Working Group (3–6 March, 2011, Durham, NC, USA), bringing together palaeontologists, molecular evolutionists and bioinformatics experts to present perspectives from disciplines that generate, model and use fossil calibration data. Presentations and discussions focused on channels for interdisciplinary collaboration, best practices for justifying, reporting and using fossil calibrations and roadblocks to synthesis of palaeontological and molecular data. Bioinformatics solutions were proposed, with the primary objective being a new database for vetted fossil calibrations with linkages to existing resources, targeted for a 2012 launch.

scholarly journals Molecular Phylogenetic Diversity and Biological Characterization of Diaporthe Species Associated with Leaf Spots of Camellia sinensis in Taiwan

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1434
Author(s):  
Hiran A. Ariyawansa ◽  
Ichen Tsai ◽  
Jian-Yuan Wang ◽  
Patchareeya Withee ◽  
Medsaii Tanjira ◽  
...  
Keyword(s):  
Camellia Sinensis ◽  
Leaf Spot ◽  
Phylogenetic Trees ◽  
Fungal Infections ◽  
Elongation Factor ◽  
Fungal Species ◽  
Tea Leaves ◽  
Phenotypic Characters ◽  
Leaf Spots ◽  
Molecular Phylogenetic

Camellia sinensis is one of the major crops grown in Taiwan and has been widely cultivated around the island. Tea leaves are prone to various fungal infections, and leaf spot is considered one of the major diseases in Taiwan tea fields. As part of a survey on fungal species causing leaf spots on tea leaves in Taiwan, 19 fungal strains morphologically similar to the genus Diaporthe were collected. ITS (internal transcribed spacer), tef1-α (translation elongation factor 1-α), tub2 (beta-tubulin), and cal (calmodulin) gene regions were used to construct phylogenetic trees and determine the evolutionary relationships among the collected strains. In total, six Diaporthe species, including one new species, Diaporthe hsinchuensis, were identified as linked with leaf spot of C. sinensis in Taiwan based on both phenotypic characters and phylogeny. These species were further characterized in terms of their pathogenicity, temperature, and pH requirements under laboratory conditions. Diaporthe tulliensis, D. passiflorae, and D. perseae were isolated from C. sinensis for the first time. Furthermore, pathogenicity tests revealed that, with wound inoculation, only D. hongkongensis was pathogenic on tea leaves. This investigation delivers the first assessment of Diaporthe taxa related to leaf spots on tea in Taiwan.

A fossil record of land plant origins from charophyte algae

Science ◽  
2021 ◽  
Vol 373 (6556) ◽  
pp. 792-796 ◽  
Author(s):  
Paul K. Strother ◽  
Clinton Foster
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Phylogenetic Signal ◽  
Land Plant ◽  
Fossil Plants ◽  
Fossil Plant ◽  
Molecular Phylogenetic ◽  
History Of ◽  
Time Gap ◽  
Evolutionary Continuity

Molecular time trees indicating that embryophytes originated around 500 million years ago (Ma) during the Cambrian are at odds with the record of fossil plants, which first appear in the mid-Silurian almost 80 million years later. This time gap has been attributed to a missing fossil plant record, but that attribution belies the case for fossil spores. Here, we describe a Tremadocian (Early Ordovician, about 480 Ma) assemblage with elements of both Cambrian and younger embryophyte spores that provides a new level of evolutionary continuity between embryophytes and their algal ancestors. This finding suggests that the molecular phylogenetic signal retains a latent evolutionary history of the acquisition of the embryophytic developmental genome, a history that perhaps began during Ediacaran-Cambrian time but was not completed until the mid-Silurian (about 430 Ma).

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